of chicago



Feb. 14, 1933. s. P. KlNNEY COMBUSTION APPARATUS Filed July 1929Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE SELWYNE I. KINNEY, OFCHICAGO, ILLINOIS, ASSIGNOR T H. A. BRASSERT & COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS COMBUSTION APPARATUSApplication filed July 1,

This invention relates to a new and improved combustion apparatus andmore particularly to apparatus for controlling the combustion ofmetallurgical gases in apparatus such as hot blast stoves or the like.

In hot blast stoves and other apparatus which burn metallurgical gasessuch as a blast furnace and producer gases, their combustion takes placein restricted chambers.

The gas, together with the air necessary for combustion, are usuallyintroduced into such chambers by means of a. mixing valve or burner. Inburning such gases it has been ditficult and in many cases impossible toavoid pulsation during combustion. The pulsations are due to the factthat the rate of propagation of the flame in the combustible orexplosive mixture of gas and air is greater than the velocity of themixture. As ignition takes place the flame has a tendency to flash back,causing a vibration or pulsation. These pulsations may occurcontinuously or substantially continuously during the combustion.

Even with the most efiective mixing burners and automatically correctproportioning of gas and air, it has not been possible in many cases toavoid the pulsation. The disadvantages of pulsating combustion are verygreat. This combustion takes place normally in combustion chambersformed of brick work and in the case of hot blast stoves or otherregenerative apparatus, the brick work in the combustion chambers or 35flues may become loosened with the result that the brick fall out andblock the chamhere or flues. In such structures the pulsation may besuliicient to gradually loosen the brick work in the checkerwork andeventually the whole structure may collapse. Furthermore where theserepeated explosions occur in steel jacketed structures such as blastfurnace stoves, the pulsations shake the entire steel structure,loosening bolts and rivets, and may be responsible for failures of theshells of the stoves. These vibrations and shakings may cause leakage inthe rivet seams, particularly where the burner casting is riveted ontothe shell. These pulsa- 5 tions also seriously affect the burners-them-1929. Serial No. 375,197.

selves which suffer from the vibration and require more than usualrepairs. Where such pulsations are present and automatic mixing burnersare used the correct proportion of gas and air is not as reliable orcorrect as when the propagation of flames occur smoothly and withoutpulsation. Due to this fact less complete combustion can be efiiected'and the affect of the pulsation'may be cumulative. v

It is an object of the present invention to provide new and improvedcombustion ap paratus and more particularly apparatus whereby pusationduring combustion may be avoided.

It is a further object to provide apparatus comprising means adapted tobe extended across a. combustion passageway or chamber, which means willserve to prevent passage of flames. I

It is also an object to provide such flame interrupting means adapted tooperate through lowering the temperature of the gas and air mixture orthrough increasing the gas velocity due to a decrease cross-sectionalarea for passage of the gaseous mixture.

It is an additional object to provide apparatus of this character whichmay be installed in existing combustion chambers and passages withoutmaterial alteration therein.

It is also an object to provide a construction adapted to resist hightemperatures and further adapted for commercial production andinstallation.

Other and further objects will appear as the description proceeds. a

I have shown such preferred embodiments of my invention in theaccompanying drawing in which Figure 1 is a fragmentary vertical sectionof the lower portion of a hot blast stove;

Figure 2 is a section taken on line 2--2 of Figure 1; 95

Figure 3 is a view similar to Figure 2 but showing a modified form ofconstruction;

Figure 4 is a face view on an enlarged scale of a section of the screenshown in Figures 1 and2; and

Figure 5 is a section taken on line 5-5 of Figure 4.

In the drawing with particular reference to Figures 1 and 2, thebrickwork of the lower portion of a hot blast stove has been shown at 11enclosed within the metal casing 12. The metal flange 13 is secured tothe metal casing or shell 12 and this flange serves for the connection.of a mixing valve or burner for the introduction of a combustiblemixture of gas and air into the combustion passageway 14, which leads tothe combustion chamber 15 of the hot blast stove. This combustionpassage 14 takes a tortuous path.

and has a vertically extending portion 16.

The chain screen 17 extends vertically in the vertical section 16 of thepassage 14 and is suspended from the bolts 18 which extend through thebrickwork 19 constituting the upper portion of the passageway 14. Ametal plate 20 is shown housing the brickwork 19 and serving todistribute the load from the bolt 18 over the brickwork. This foraminousscreen 17, as shown in Figure 2, covers substantially the ent-irecross-sectional area of the passageway 14 and is made up of interlinkedrings as shown in detail in Figures 4 and 5. A modified form ofconstruction is shown in Figure 3 in which the screen 21 made up of barsor rods, is retained in the same relative position as the chain curtain17, the screen 21 being held in place by the pins 22, which are set intothe surrounding brickwork 23.

The rings of the chain curtain 17 or the bars of the screens 21 may beformed of any desired heat resistant material. For example they may beformed of metal where the temperatures are such as to permit the use ofmetal. Where higher temperaturesare to be encountered they may be formedof ceramic material or may be formed of metal coated or covered withceramic or refractory material.

It will be noted that the curtains 17 or screens 21 as placed in thetortuous passageways 14 are greater in area than the direct crosssectional area of the passageway. With the screen or curtain extendingas shown the total screen area thus may be materially greater than thecross-sectional area of the passage, and the screen may have aneffective area for the passage of gases fully equal to thecross-sectional area of the passage, so that it does not serve as aconstriction to materially retard the passage of gases.

The screen will serve to effectually prevent propagation of the flameback of the screen. Combustion will take place in the chamber 15 and inthe upper portion of the passage 14 between the screen 17 and thechamber 15. No combustion, however, will take place between the screen17 and the burner attached to the flange 13. The action flowv This speedof gas flow through the screen may be, therefore, brought to a pointwhere it"exceeds the velocity of flame propagation, so that no flamewill pass through the screen. The cause of pulsation is a greatervelocity of flame propagation than the velocity of the mixture of gasand air. The principal effectiveness of a metallic screen compared tothe use of refractory material, however, consists of its dissipation ofheat. The temperature of the gas is lowered below the ignition point,and combustion is thus stopped at the screen.

While I have shown my invention as applied to the combustion passagewaysof a hot blast stove it will be obvious that it may be applied for usein combustion chambers or flues or furnaces where air and gas mixturesare burnt, and wherever a pulsation results due to intermittentcombustion. It will be understood also that the nature of the screen mayvary under different conditions and it may be wholly built of steel orother metal rings or rods or wires, or of any suitable high temperatureresisting alloys. It also may be formed in whole or in part ofrefractory material, the refractory material being in the form of rods,bars or bricks or made up solidly in the form of a perforated screen orcurtain. The refractory material would preferably be used where veryhigh temperatures prevail at the point where the screen is to beapplied.

lVhile I have shown certain preferred embodiments of my invention by wayof illustration, it is capable of change and modification to meetvarying conditions of use and installation, and I contemplate suchchanges and modifications as come within the spirit and scope of theappended claims.

I claim: I v

1. Combustion apparatus comprising a passage carryinga gaseouscombustible mixture and a screen of heat resistant material extendingacross the passage area, said screen comprising metallic links andhanging vertically in the passageway.

2. In-a hot blast stove, a tortuous passageway for carrying acombustible mixture of gas and air, said passageway having a verticallyextending portion, a chain curtain hung in said vertically extendingportion and extending across substantially the entire passage area.

3. In a hot blast stove, a passageway in said stove connecting at oneend to the com- 'bustion chamber and having a burner opening at theother end, said passageway having a substantially vertical intermediateportion, and a vertically extending perforate screen extending acrosssubstantially the entire effective passage area in said verticalportion.

4. In a hot blast stove, a passageway in said stove connecting at oneend to the combustion chamber and having a burner opening at the otherend, said passageway having a. substantially vertical intermediateportion, and a vertically extending perforate screen comprising asuspended metallic chain curtain extending across substantially theentire effective passage area in said vertical port-ion the effectivearea for passage through the screen being not less than thecross-sectional area of the passage.

Signed at Chicago Illinois, this 22nd day of June, 1929.

SELWVYNE P. KINNEY.

